Self-emptying pressure vessels



2 Sheets-Sheet 1 Filed March 15, 1957 cw y WW3 vie f JDMWMW W W7. 5Q. gm

APril 1961 A. RILINGER ETAL 2, 78,144

SELF-EMPTYING PRESSURE VESSELS Filed March 15, 1957 2 Sheets-Sheet 2fieZ-muz- WeLmeyBr A thw- United States Patent 2,978,144 SELF-EMPTYINGPRESSURE VESSELS Alfons Rilinger and Helmut Wehmeyer, Konigslutter amElm, Germany, assignors to Roto-Werke A.G., Konigslutter am Elm,Germany, a German company Filed Mar. 15, 1957, Ser. No. 646,486 Claimspriority, application Germany Mar. 19, 1956 4 Claims. (Cl. 222-95) Thisinvention relates to self-emptying pressure vessels. It is known to use,for a variety of purposes, selfemptying pressure vessels containingliquid or paste-like active substances, wherein the active substancesare constantly acted upon by driving media. Hence, when a valve ornozzle on the vessel is opened, the active substance is urged, forinstance as a spray, out of the tank without any need for mechanical ormanual pressure. The driving or urging medium conventionally takes theform of liquefied gases such as, for instance, chloromethyl, propane,butane, Freon (difluordichloromethane) or the like which evaporate atroom temperature of for example 20-30 C.

For instance, there are vessels known as aerosol regulating vesselswherein a liquid driving medium is mixed with the active substance andexpels or entrains it when the vessel closure means are opened. In thiscase, therefore, a mixture of driving medium and active substance issuesfrom the vessel.

It has also been proposed to ink printing presses by urging the ink, bymeans of such a driving medium, from the vessel or recipient towards theinking station, the ink having to be mixed with the driving medium as inthe case of the aerosol regulating vessels. However, this principle canbe applied with advantage only where an ink film of very reducedthickness is required, since only highly fluid ink can be used. Theadmixed driving liquid helps to produce an ink film of very reducedthickness by flowing in spray form and thereafter volatilizing. On theotherhand, this principle cannot be used, for instance, on presses whichrotate at high speed and in which thickly viscous ink is applied inrelatively large quantities and spread by rubbing. In these cases it hasbeen proposed that the printing ink should be kept separate from thedriving liquid in the vessel, for instance, through the agency of apiston surrounded by a sleeve in intimate engagement with the cylinderinner wall. This arrangement has the advantage that, since the drivingmedium and active substance are separated from one another, any desiredactive substance can be used in its pure form and with its consistencyunimpaired. Also, since the same quantity of driving medium is retaineduntil all the active substance has been removed from the vessel, muchless driving medium is needed than with the aerosol principle, whichentails a continuous reduction in the quantity of driving medium as itissues with the active substance. A great disadvantage of the pistonarrangement is that the vessels must be completely cylindrical and freefrom all scams or bulges. Piston-type vessels are therefore,

costly and complicated, and all the more so since the vessels also serveas dispatch vessels and slight dents or the like are unavoidable. beused, relatively large losses are incur-red.

To obviate this disadvantage, according to another proposal the pistonwas replaced by a bag of rubber, plastic or other flexible substance,the base of the bag being adapted to move freely and the other and openend thereof. being clamped between the end face of the cylindricalSincedented vessels cannot flexible tubes are introduced into andsecured to the 2,978,144 Patented Apr. 4, 1961 the other andlarger-volume chamber near the vessel closure means received the activesubstance. When the said closure means are removed or.opened, theevaporating driving medium acts upon the pushed-over bag base and urgesthe active substance towards the closure means until the same arereclosed and the density by volume determined by the kind and quantityof driving medium and, by the room temperature is reattained.

In itself this process is ideal but it was often found in practice thatthe active substance issued very sluggishly, if at all, from vesselswhich were half-full or less. The reason is that, after slight emptyingof the vessel, the evolved gas expanded the bag along the vessel innerWall to the vessel closure means and finally squeezed the bag over theexit aperture, thus completely preventing the active substance fromissuing from the vessel. Also, the driving gas, which acted upon the bagat constant pressure, could difluse to some extent, and all the more sosince defects in the texture of the flexible bag are not initiallyperceptible and such defects readily. occur, due to decomposition of thesubstances or disturbances to the structure, when the plastic tubespreferably employed are welded together. As a result, the driving mediummixes with the active substance, which is thus altered and there is areduction in the quantity of the driving medium,

cylindrical body, while the other end of the flexible tube is closed bybeing pressed flat and is secured at the opposite end of the vessel to aside wall thereof, for instance, by clamping between the base and thewall of the vessel, the

driving liquid being received in a chamber inside the vessel body at theapex of the flexible tube, the same being formed into a pointed bag. V

Preferably, a second flexible tube closed at one end is provided for thedriving liquid, the open and closed ends of the second tube beingsecured to the vessel in the same way, but in inverted relation to theflexible tube containing the active substance, an open chamber beingprovided near the bottom end of the flexible tube for the activesubstance inside the .vessel, the last-mentioned open chamv, ber servingto receive that part of the second. flexible tube which contains thedriving liquid.

An embodiment of the invention will be described by way of example withreference to the accompanying drawings in which: 7

Figures 1 to 9 diagrammatically illustrate how the two vessel, and

Figures 10 to 12 illustrate a finished vessel and show how operationsproceed therein when the closure means have been opened.

Figure l is a plan view of the hollow cylindrical body of a liquidvessel 1 without cover and base. As can be seen in Figure 2, which is asectional view taken through s am Initially, the tubes 2 and 3' extendon both sides of the cylindrical vessel 1 beyond the end faces. First,as can be seen in Figure 3, the top end of the tube 2 is closed andbentaround the top edge of the vessel wall outward- 1y, whereafter, as canbe seen in Figure 4, the adjacent second tube 3,is opened wide at thetop and stretched right around the topend edge of the cylinder 1, sothat it acquires the shape shown in Figure 5 with a top circularaperture. That open part of the tube 3 which extends around the top endedge of the cylinder 1 also engages over the top end of the tube 2.

Thereafter, preferably through the agency of a cylindrical former whichhas an inclined lower part and which is shown hatched in Figure 7, theflexible tube 3, which is intended to' receive the active substance inthe embodiment illustrated, is pressed against the cylinder inner wall(Figure 6) and urges the tube 2 in the flat state between the said innerwall and the tube 3, the inclined part of the former producing a spacefor the tube 2 at the bottom to receive the driving medium. The tube 3,which is kept open at the top is closed only at the bottom (just likethe tube 2, which is closed at the top) and bent aroundthe outside ofthe bottom end edge of the vessel Wall in order that this tube may beclosed and secured by the subsequent fitting of the base (Figure 7).

The free bottom end of the tube 2 is opened wide to form'a shallow bag(Figure 8) and stretched around the bottom end edge of the cylinder 1(Figure 9), just like the tube 3 was stretched around the top end edge;the open part of the tube 2 now surrounds the bottom end edge of thecylinder 1 and also engages over the bottom end of the tube 3. A shallowbag is thus produced for the relativelysmall quantity of driving media.

After the active substance has been introduced into the chamber formedby the tube 3, a cover 4 (Figure 10) having a closure means or valve orthe like is fitted to the cylinder 1 and secured. This step also securesand seals in non-releasable manner the closed end of the tube 2 and theopen end of the tube 3. The vessel is then turned the other way round,the driving liquid is charged into the funnel-shaped space of the tube 2and the base 5 (Figure 10) is fitted and secured in sealingtight mannerto the cylinder 1, so that the closed end of the tube 3 and the open endof the tube 2 are closed tight. After closure, so much of the drivingliquid evaporates at room temperature that the predetermined pressure isattained in the vessel, that is, the same has assumed the shape shown inFigure 10.

Figure 10 illustrates the vessel ready for dispatch. It has been chargedwith active substance W and driving medium T and fitted with a closedclosure means 6. When the same is opened, the pressure produced by theevaporating driving medium urges the active substance out of the vessel.Because of the .manner in which the flexible tubing is secured, thedriving gas is so deflected that the pressure can be applied only fromthe vessel base, the tube 2 therefore, gradually assumes the shape shownin Figure 11.

The final phase of operation is illustrated in Figure 12. The drivingmedium has urged the two tubes fast against the vessel inner wall andthus the air is trapped which may be in the vessel but outside thetubing, at one end in the space L. This air assists operation to theextent that the remainder of the active substance is urged out of thevessel.

It has been found in practice that only a small part of the activesubstance which adhered to the walls of the conventional vessels usedheretofore remained in vessels having the flexible tube arrangementaccording to the invention. This reliable and substantially completeconsumption of the active substance is of itself a considerabletechnical advance, and another advantage is that the use of flexibletubing instead of bags obviateswelding s earns on the base, Asa result,and more particularly where a number of foil layers are provided toseparate 4 the driving medium from the active substance, a diffusion ofthe driving mediuni into the active substance is substantially obviated.

In a simplified embodiment, the tube 2 can be omitted and merely thetube 3 can be so secured to the base and cover that the expansion of thedriving gas from the vessel base towardsthe exit aperture acts upon theactive substance. For instance, to produce this effect the tube. issecured in. the manner hereinbefore described. It then forms a bag whichis wide open at the vessel cover and which extends right around the endedge of the cylinder 1. The flexible tube thus folded in between thecylinder edge and the cover extends along the cylinder inner wall to thebase, Where it is closed and, while in the closed state, bent asideoutwardly and laid around the cylinder end edge. This closed tube end isalso non-releasably folded in on the vessel base. If the tube is securedin this way, it cannot place itself before the exit aperture of thevessel or become so kinked that the active substance in the bag isprevented from issuing. The pressure of the driving medium charged intothe open chamber on the vessel base Will always take effect where boththe active substance and also the tube ofier least resistance. In thetube securing arrangement according to the invention, when the tube isfull the resistance is greatest near the vessel cover, because of thetension of the tube, the resistance decreasing towards the vessel base.This ensures that the substance is urged uniformly out of the vesselwithout disturbance. Preferably however, in order to reduce possiblediffusion of the driving gas as far as possible, at least two flexibletubes will be provided in the vessel in the manner hereinbeforedescribed.

Another considerable advantage of using two tubes is that the activesubstance issues until the tube is completely empty, because the airwhich acts at the termination of operations remains separate from theactive substance and from the driving medium and is urged towards thecover to urge out the remaining active substance. If only one flexibletube is used, the air is disposed in the driving gas chamber and cannotassist operations, so that there is bound to be a residue of activesubstance.

The pressure vessel can of course be constructed in other ways. Forinstance, other means could be provided for securing the tubes to thevessels. For instance, instead of stretching the tubing around theoutside of the cover edge, an internally fitted ring could be used. Thetubes might be produced with one end closed or with a special extensionfor clamping to the vessel.

The pressure vessel need not of course be cylindrical but is withadvantage cylindrical or oval to ensure that space is used efiiciently,in which case the cylindrical base surface must form a circle, ellipseor other closed curve.

We claim:

1. A self-emptying pressure vessel for active substances, comprising abody, a cover provided with an exit aperture for the active substance, abase, the cover and the base being rigidly secured to said body at itsupper and lower end respectively, a flexible tube adapted to receive theactive substance, said tube having been widened as much as possible toadapt it to the inner diameter of the vessel and having one open endsecured to that end of the vessel containing the exit aperture, theother end of the flexible tube being closed by being pressed flat insuch a way that the one side thereof has a somewhat greater length thanthe opposite side and is secured at the opposite end of the body to thelower edge thereof, and a chamber provided inside the vessel body at theoutside of the closed end of the flexible tube, and adapted to receive adriving liquid which evaporates at temperatures of 20-30" C.

2. A self-emptying pressure vessel for. active suba c .wmprising body, a.Y ..P 9. .ids4 went exit aperture for the active substance, a base, thecover and the base being rigidly secured to said body at its upper andlower end respectively, a flexible tube adapted to receive the activesubstance, said tube having been widened as much as possible to adapt itto the inner diameter of the vessel and having one open end secured tothat end of the vessel containing the exit aperture, the other end ofthe flexible tube being closed by being pressed flat in such a way thatthe one side thereof has a somewhat greater length than the oppositeside and is secured at the opposite end of the body to the lower edgethereof, and a second flexible tube having an open end and being closedat the other end and provided for the driving liquid which evaporates attemperatures of 20- 30 C., the open and closed ends of the second tubebeing secured to the vessel in inverted relation to the flexible tubecontaining the active substance so as to provide an open chamber nearthe bottom end of the flexible tube for the active substance inside thevessel, and the last-mentioned open chamber serving to receive that partof the second flexible tube which contains the driving liquid.

3. A pressure vessel according to claim 2, wherein both the closed endsof the flexible tubes and the open ends are secured to opposite endedges of the vessel body by being provided around or pushed over suchedges and clamped between the said edges of the vessel body and thecover and the base respectively.

4. A pressure vessel according to claim 2, wherein the open end of onetube is pushed over the closed end of the other tube which is laidaround the outside of the end edge of the vessel body, and is retainedin position by bent over edges of the cover or the base and clampedbetween the said edges of the vessel body and the cover and the baserespectively said tube ends also sealing the vessel in the regions wherethey are secured.

References Cited in the file of this patent UNITED STATES PATENTS ThomasJune 2, 1959

